When he won the U.S. Open on Monday night, his third Grand Slam title of the year, Novak Djokovic didn’t dance to the hip-hop music blaring over the Arthur Ashe Stadium loudspeakers in New York. His delirious entourage – which included his coach, uncle, manager, trainer and girlfriend – bounced in their seats. He didn’t eat some strange substance, like at Wimbledon, where he chomped on grass after winning the championship. (Though he did give the hard court surface a little peck.) He didn’t pull out one of his famous impersonations, or act goofy for the crowd, which he’s fond of doing.

No, Djokovic just slouched in his chair, taking it all in. After the type of season this guy has had, he certainly deserves a little rest.

Turns out that tearing up men’s tennis can be exhausting. “I feel drained,” the Serbian player said after beating Rafael Nadal, 6-2, 6-4, 6-7, 6-1, in the final. He was wearing a backwards “FDNY” cap, in honor of 9/11, while speaking with the media. “Emotionally and physically.”

Djokovic is now 64-2 in 2011, good for a crazy .970 winning percentage so far. (John McEnroe has set the standard for dominance in a season with his 82-3 record, and .965 winning percentage, in 1984.) “What this guy is doing this year is an unbelievable thing,” Nadal said in his gracious on-court speech after the match. “What you’ve done this year,” Nadal said, turning to face Djokovic, “will probably never be repeated.”

It’s tough to call a four-set match epic. But this 2011 final was pretty close. Double-digit shot rallies were common. At times, the players seemed to be hitting at one another, to see who would screw up first. Eventually, one of them, especially Djokovic, would hit the ball at just the right angle for a winner. (Djokovic finished the match with 55 winners, while Nadal had 33.) Throughout the match, Djokovic was the aggressor. He approached the net 47 times, and won 66% of those points; Nadal only came up 17 times, and won 76% of his approaches. “I had to make the points short,” Djokovic said, explaining his strategy. “He’s physically fitter.”

Djokovic mixed things up. In the first set, which he won 6-2, he hit a few pretty drop shots that fooled Nadal. Djokovic is now 6-0 against Nadal in 2011, and he seemed to be toying with him. Throughout the match, his shots were sharper, and flatter, than his opponent’s. Nadal blooped a few too many balls over the net; they looked like shots a weekend hack could return. And he admitted that his serve was sub-par. “I didn’t start the points with an advantage tonight on my serve,” Nadal said. It cost him.

But Nadal, as usual, never folded. His third set charge electrified the New York crowd, which was letting off some post-work steam. (The match started a little after 4 p.m., with many empty seats; by the end, the place was packed.) It’s not that the fans disliked Djokovic. They just wanted to see more tennis. Nadal won the third set tiebreaker, and held his serve in the first game of the fourth set. But before the crowd could get too explosive, Djokovic called for a medical timeout. His ribs, legs and back were hurting. He took a painkiller, and then put a hurt on Nadal, winning the next six games, and the match.

Djokovic’s record has sparked debate among the racquet-heads. Where does he rank among the all-time greats? We haven’t seen a single player rule the sport in this way since Roger Federer in the mid-2000s. Will we be comparing Djokovic’s game to a religious experience?

He’s not quite there yet. Part of this has to do with his style: he’s not as fluid as Federer, and Federer’s grace transcended the game. Using the totally subjective, unscientific method of evaluating athletes – when I watch this guy, am I in awe? – Djokovic falls a hair short. But if he keeps winning, Djokovic will just overwhelm his doubters.

And he’ll keep loving every minute of it. This year, Djokovic made a famous change to his diet and stopped eating gluten after a nutritionist discovered he was allergic to the protein. After the match, someone asked him what he ate the night before. “I will give you a simple answer,” Djokovic told the media. “Last night, I didn’t have any gluten, and tonight, I will have a bunch of gluten, and alcohol.” The room cracked up.

Djokovic’s team ordered champagne to the locker room. In an Ashe Stadium corridor, Djokovic took congratulatory calls on a cell phone. Martina Navratilova was passing through the hallway, and was introduced to Djokovic’s long-time girlfriend, Jelena Ristic. “What a season,” Navratilova told Ristic. “It’s unbelievable. And it probably won’t ever happen again.

“Enjoy it while it lasts.”

Sean Gregory is a staff writer at TIME. Find him on Twitter at @seanmgregory. You can also continue the discussion on TIME’sFacebook page and on Twitter at @TIME.